The present invention relates generally to pad mounted underground electrical power distribution systems, and more particularly to a safety interlock or latching means operatively associated with the fuse panel upon which the encapsulated current limiting power fuse is mounted such that the fuse must be electrically isolated prior to removal of the fuse panel and the fuse from the power distribution system housing enclosure when service is to be performed upon the fuse panel and/or the fuse mounted thereon, such as, for example, during replacement of the fuse panel and the associated fuse, or replacement of the encapsulated current limiting power fuse per se.
In conjunction with conventional pad mounted underground electrical power distribution systems, for example, it is occasionally necessary to service a particular line, circuit, or phase thereof through means of replacement of the associated encapsulated current limiting power fuse, or the entire fuse panel, which may have become damaged during operation of the system. In order to enhance or maximize the operational safety conditions of the system for the lineman or service operator personnel, it is imperative that the damaged fuse and/or its fuse panel be electrically isolated prior to the lineman or service operator personnel performing the necessary repair or replacement work thereon.
Ordinarily, the various circuits, lines, or phases comprising the electrical power distribution system are arranged in pairs and the rear terminal ends of the encapsulated current limiting fuses are electrically interconnected by means of encapsulated vacuum switchgear apparatus. In operation, one of each of the paired circuits, lines, or phases is actually in operation thereby providing electrical power service to the designated customers or consumers while the other one of each of the paired circuits, lines, or phases is not in operation but is disposed in a stand-by or back-up mode and is readily capable of being placed into service. A single switchgear installation is thus provided for service in connection with each pair of circuits, lines, or phases, and the switchgear installation comprises a pair of switch mechanisms which may be opened or closed to provide or interrupt electrical power to or from the line fuses, respectively. In this manner, when one of the paired line fuses, for example, becomes damaged and needs to be replaced, the switchgear switch mechanisms are operated in such a manner as to open the switch associated with the damaged fuse and its circuit or line thereby terminating power to such fuse and its circuit or line, while the other switch mechanism is closed so as to now provide electrical power to the back-up or stand-by circuit, line, or phase thereby bringing such circuit, line or phase into operation. In this manner, the electrical power service is restored to the designated customer or consumer within a minimum amount of time.
It is therefore to be appreciated that in accordance with the foregoing, and in furtherance of the provision of safe conditions attendant the replacement of the damaged fuse and/or fuse panel, electrical power to the rear terminal of the damaged fuse has been interrupted or terminated, however, the front terminal of the damaged fuse is still connected within its associated line, circuit, or phase which does not provide the lineman or repair service operator personnel with a safe condition. A need therefore exists for a means or system which will insure the fact that the front or forward terminal of the damaged fuse will be electrically disconnected prior to access being permitted to the fuse panel and its associated fuse. In this manner, the fuse and its associated fuse panel will be entirely electrically isolated and rendered completely safe to be approached and handled by the lineman or repair service operator personnel. An example of a system similar to that just proposed is disclosed within U.S. Pat. No. 4,250,357 issued to Kenneth E. Hanke. In this system, the insulated line conductors and their associated elbow connectors must be removed from the front or forward terminals or bushings of the fuses before the fuse panels and their associated fuses can be pivoted forwardly and downwardly in order to permit access to the fuses or other components, or in order to permit removal or replacement of the entire fuse panel. This system, however, is seen to be quite complex in that a redundant, dual-latch system is provided for releasing or latching the fuse panel within its enclosure panel, and in addition, as previously noted, the latching system is utilized in conjunction with pivotable fuse panels.
Accordingly, it is an object of the present invention to provide a new and improved electrical power distribution system.
Another object of the present invention is to provide a new and improved pad mounted underground electrical power distribution system.
Still another object of the present invention is to provide a new and improved fuse mounting arrangement for pad mounted underground electrical power distribution systems.
Yet another object of the present invention is to provide a new and improved fuse mounting arrangement for pad mounted underground electrical power distribution systems which overcomes the various safety deficiencies of conventional electrical power distribution systems.
Yet another object of the present invention is to provide a new and improved fuse mounting arrangement for pad mounted underground electrical power distribution systems which provides the necessary safety environment for lineman or repair service operator personnel during a service operation being performed upon the fuse panel or the power fuse per se.
Yet still another object of the present invention is to provide a new and improved fuse mounting arrangement for pad mounted underground electrical power distribution systems which includes a safety interlock or latching means operatively associated with the fuse panel and the encapsulated current limiting power fuse mounted thereon which prevents the fuse panel and its associated fuse form being withdrawn from the power distribution system housing enclosure prior to disconnection of the insulated circuit line conductors and their associated elbow connectors from the front or forward fuse terminals or bushings.
A further object of the present invention is to provide a new and improved fuse mounting arrangement for pad mounted underground electrical power distribution systems which includes a safety interlock or latching means operatively associated with the fuse panel and the encapsulated current limiting power fuse mounted thereon which prevents the fuse panel and its associated fuse from being withdrawn from the power distribution system housing enclosure in order to gain access to the rear portion of the fuse panel and the fuse mounted thereon prior to electrical isolation of the fuse panel and the power fuse mounted thereon by requiring the insulated circuit line conductors and their associated elbow connectors to be initially disconnected from the front or forward terminals or bushings of the fuse.
A still further object of the present invention is to provide a new and improved fuse mounting arrangement for pad mounted underground electrical power distribution systems which includes a safety interlock or latching means operatively associated with the fuse panel and the encapsulated current limiting power fuse mounted thereon which is relatively simple in structure and relatively simple to operate by means of the lineman or repair service operator personnel during the performance of a service operation whereby access to the rear surface of the fuse panel and the power fuse mounted thereon may be easily and rapidly achieved under entirely safe operating conditions.
A yet further object of the present invention is to provide a new and improved fuse mounting arrangement for pad mounted underground electrical power distribution systems which includes a safety interlock or latching means operatively associated with the fuse panel and the encapsulated current limiting power fuse mounted thereon which is especially adapted for use in conjunction with fuse panels which are slideably mounted within the power distribution system housing enclosure.